Under the Clean Water Act (CWA) and other statutes, the federal government regulates nearly all utility water use and discharge. Key aspects of utility operations that are regulated under the Act include:

Cooling water: As noted, nearly all power plants withdraw substantial amounts of cooling water, usually from lakes, rivers, estuaries or oceans. This water is used to condense steam and provide cooling for plant generating systems. Facilities use the water from nearby waterbodies for this cooling. EPA directives that address cooling water designate technology-based performance standards or alternatives that a power plant must adopt to protect fish and other aquatic species and local watersheds. Researchers in the electric power industry, government and academia have been studying the effects of power plant cooling on aquatic ecosystems and have been working to develop strategies for fish protection for more than 35 years. One consistent finding is that the environmental impacts of power plant cooling vary widely from plant to plant and depend largely on local conditions. The best solution for fish and wildlife protection at one locale may not be the best at another.

Discharge permits: The CWA requires all point sources dischargers to obtain a discharge permit (known as National Pollutant Discharge Elimination System or § 402 permits). The NPDES permit is the principal vehicle by which individual dischargers are regulated. Both technology-based and water quality-based limits (the two CWA programs for controlling discharges) are administered under the NPDES permit programs. EPA is currently revising the steam electric effluent guidelines rule which covers wastewater discharges from utility power plants.

TMDLs: A Total Maximum Daily Load (TMDL) is the amount of a pollutant that a water body can absorb on a daily basis and still meet federal and state water quality standards. Under the CWA, each state must identify and formally list waters that do not meet water quality standards and, when appropriate, develop TMDLs for those waters. The types of pollutants and allowable amount of each pollutant vary for each "impaired" water body. EEI member companies have taken a proactive role working with federal, state and local authorities to accurately and reliably determine appropriate TMDLs for water bodies throughout the country.